Process for concentrating unsaturated hydrocarbon material



Patented Mar. 5, 1 946 ,i f v I 23.95am 4 PROCESS. FiJR CGNCENTRATING UNSATU- RATED ROCARBON MATERIAL Frederick W. Breuer, Haveri'ord. Pa", assignor to The United Gas Improvement ilompany, a cornoration of Pennsylvania.

No Drawing. spartan July 24, 1942, Serial No. 452,200

13 (Claims.

This invention pertains generally to the recovery of unsaturated hydrocarbons from 'mixed gases containing the same and pertains particularlyto such operations wherein salts of metals ti groups. 1 and 2 of the periodic system are employed. v

I have found that when solid dry salts of the character described (that is, salts substantially free from water) are employed for this purpose and whether or not the mixturecontaining the unsaturated hydrocarbons is in the liquid or vapor phase, there is a distinct tendency for polymerization and other side reactions to take place resulting not only in a loss of unsaturated hydrocarbon material but frequently also in deposits upon the particlesof solid dry reagent. Such deposits not only reduce the activity of the reagent particles but also greatly increase the tendency for the particles to coalesce with a further reduction in activity and a substantial increase in operating difiiculties.

I have discovered that side reactions of the character described as well as the deposition of reaction products upon the reagent particles may be very substantially reduced or prevented by mixing with the solid dry reagent or with the mixture to be, ,or undergoing, treatment, an organic base.

Solid dry salts of metals of groups 1 and 2 'of the periodic system and particularly monovalent salts of heavy metals of these groups, such as halides, nitrates, sulfates, phosphates, formates, acetates, propionates, carbonates and lactates of copper, mercury andsilver may be employed for the removal or recovery from hydrocarbon mixtures, either in the vapor or liquid phase, of diolefines and/or olefines by the formation of an association product of one or more of said unsaturated hydrocarbons with one or more of said salts under. suitable temperature and pressure conditions, which association product may be afterward dissociated such as by an elevation in temperature and/or reduction in pressure, usually after separation from the unreacted material, to regenerate the unsaturated hydro-' carbon or hydrocarbons and the reagent salt.

tivity of the reagent to such an extent as to require complete renewal thereof with fresh material.

By the operation of my invention the useful life of the reagent is greatly extended and the loss of unsaturated hydrocarbons by virtue of side reactions is greatly reduced.

Under suitable conditions of temperature and pressure, diolefln'es may be made to selectively react with reagents of the type described in pref erence to olefines.

Furthermore, any two or more of these classes of hydrocarbons maybe caused to react with a mass of reagent saltto form a plurality of association products which, since they have different dissociation pressures, may be dissociated selectively, such as stagewis'e, to yield each class of hydrocarbon in more concentrated form.

Moreover, any of these classes of unsaturated hydrocarbons may be selectively removed from mixtures containing other materials.

In some instances, the tendency to form solid or semi-solid secondary reaction products by polymerization or otherwise is very pronounced and whenthe reagent is in a solid dry form such secondary reaction products are deposited upon the reagent particles. Such deposits not only prevent the mixture undergoing treatment from coming into proper contact with reagent par ticles thus coated but also tend to cause the reagent particles to agglomerate to introduce processing and handling difliculties.

While any organic base may be mixed with the reagent salt, I prefer to select such organic basic materials which are either inert with respect to ,the reagent salt or of very low reactivity therewith.

Forreaction efliciency and ease of handling,

it is very desirable to maintain the solid dry reagent in finely divided form during the treatment and with surfaces uncoated with secondary reaction products. 1

Furthermore, that portion of the reagent which becomes coated with secondary reaction products represents a loss in reagent itself. When present in considerable quantity, it may reduce the ac- I also prefer to employ organic basic substances of relatively low volatility in order that they may be retained over a longer period in admixture with the reagent salt without necessity of unduly large make-up. and without undue admixture of volatilized basic material with recovered unsaturated hydrocarbons.

' In the event that any organic basic material reacts to an appreciable extent with the salts, it is preferred that such reaction product be of low vapor pressure.

It is also preferred that any salts which may be formed between the organic base, and any acidic material which might be present during the various stages of the process be readily soluble in an ordinary solvent so that, if desired, it may be readily removedfrom the reagent salt.

In addition. if desired. h ni a ma be chosen so that any salt formed therewith may have little tendency to hydrolyze in the presence of moisture, the presence of which is substantially unavoidable in industrial operations of the character under discussion.

Examples of organic basic materials which may be used in my invention are as follows:

A. Primary, secondary and tertiary alkyl amines such as methyl amine, dimethyl amine, trimethyl amine, ethyl amine, diethyl amine, triethyl amine, propyl amine, butyl amine, amyl amine, etc.

B. Primary, secondary and tertiary hydroxy alkyl amines, such as monoethanolamine, diethanolamine and triethanolamine.

C. Aromatic amines such as, aniline (phenyl amine), ortho toluidine, meta toluidine, para toluidine, benzylamine, methyl aniline, dimethyl aniline,'diethyl aniline, benzyl aniline, acetaniiide, aceto-acetanilide, 1.2,3-xylidine, 1,2,4-xylidine, 1,3,2-xylidine, 1,3,4-xylidine, 1,3,5-xylidine. 1,4,2-xylidine, and aryl amines in general.

D. Alkyl and aryl hydroxyl amines such as beta phenyl hydroxyl amine, alpha methyl hydroxyl amine and beta methyl hydroxylamine.

E. Aliphatic and aromatic quaternary ammonium bases such as alkyl and aryl ammonium hydroxides, for example, tetramethyl ammonium hydroxide. phenyl trimethyl ammonium hydroxide. benzyl trimethyl ammonium hydroxide, etc,

vantage of being powerful reducing agents, thus tending to insure the presence of reagent salt in monovalent form.

G. Amine oxides such as trimethyl amine oxide.

H. Cyclic tertiary bases such as pyridine, qui noline, isoquinoline, acridlne, alpha, beta and gamma picoline, dimethyl pyridines, trimethyl pyridines, hydrogenated pyridines, for example, piperidine.

Any desired. or suitable quantity of organic basic material may be employed.

However, it is preferred that the reagent salt shall not be suspended or floatedin a continuous liquid phase of organic basic material, for ex ample, to form a slurry.

The solid reagent salt per as may be said to be dispersed since it is employed in a disintegrated form, for example, in the form of a powder to form a mass with considerable free space between the particles thereof.

When the reagent salt is mixed with an organic basic liquid it is preferred to retain a substantial part of this free space. Accordingly, the proportion of organic basic liquid to solid salt preferably should not be sufficient to form a continuous liquid phase with solid salt particles dispersed therein, but should be restricted to such quantity that the liquid itself may be saidto be dispersed along with the solid, in which conditlon there may be said to be retained in the mass a degree of free space between the wetted particles thereof.

Thus the reagent when thus treated with the liquid differs from a slurry in that it is not freely flowing or pumpable as is the case with a slurry.

As a rule between 0.1% to by weight of organic basic material to solid reagent sa t will a give improved results, the exact amount required 'by weight of organic basic substance based upon solid dry reagent salt present will usually be very satisfactory.

Processes of the general character to which my invention may be applied relate for the most part to the selective recovery of unsaturated hydrocarbons of less than seven carbon atoms from mixtures thereof. although they are not limited thereto.

Frequently, it is found to be technically advantageous to first resort to fractional distillation or other means to narrow the boiling range of the mixture.

Thus a C? cut may be treated to separate dioleflnes from olefines or' a distillate fraction containing substantially no other dioleilne but, say,

isoprene or piperylene may be treated to segregate the respective diolefine from olefinie and any parafllnic material which might be present.

Likewise, a 04 out containing butadiene, butene and perhaps butane may be treated to segregate the butadiene in high concentration.

A C: out or a C: out might be treated to segregate propylene or ethylene respectively in high concentratiom The dioleflnes present in a given fraction may be contacted under conditions of temperature and pressure such that substantially only dioleflne materials are absorbed by the reaction mass. Then after removal of unreacted material the complex formed between the diolefine material and the reaction mass may be decomposed by elevation in temperature and/or reduction in I which has matured into Patent 2,359,020, granted September 26," 1944, and the recovery of butadiene from a mixture thereof containing other hydrocarbons by contacting the same with solid dry cuprous chloride is described in Chemical Abstracts, vol. 32, 6098-6100 (1938).

The recovery of oletlnes from hydrocarbon mixtures containing the same by contacting said mixtures with solid dry salts of the character referred to herein is described in U. S. Patent 2,116,157, dated May 3, 1938, and US. Patent 2,209,452, dated July 30, 1940.

My invention may be applied in any of the foregoing. processes with the advantages set forth herein.

If desired, any one or more organic basic materials may be applied to the solid salt prior to contact with the material to be treated in the form of a solution or suspension in a basic or non-basic liquid. if desired, care preferably beliquid in the the invention.

I original fraction,

ing taken that any liquid in the reaction mass when ready for use is substantially non-aqueous and is in the dispersed phase as distinguished from the continuous phase. I

It is understood, of course, that in a large mass of treated reagent salt a portion may contain continuous phase. The following examples will serve to illustrate Example I In a mixing vessel equipped with heating and cooling means and connected to a receiver and pressure reducing device, 24:00v grams of dry cuprous chloride powder was treated for one hour 26 grams of mixed triamyi The butanewas .anintermediate fraction was obtained by further reducing the pressure'to 40 mm. of mercury. Then upon maintaining approximately the lat-. ter pressure, the temperature was raised slowly to approximately 60 C. to obtain a 92% yield of the isoprene present in the original fraction in a concentration of 98.5%.

A very thorough examination of the reagent mass-showed the absence of any deposits thereon from the material undergoing treatment.

Example II A 70% light oil piperylene fraction, containing 24% amylenes and 6% pentanes, was concentrated according to the method outlined in Example'l, a mixture comprising 98 parts of dry, powdered cuprous chloride and 2 parts of triethanolamine being employed as the concentrathis agent.

An 85% yield of the piperylene present in the taining 98% piperylene, was obtained.

Example III light oil butadiene fraction, containing 48% butylenes and 2% butanes', was treated'with an absorbent comprising 98 parts of finely divided cuprous chloride and triethanolamine for a period of one hour at a temperature of C.. after which the butylenes and butanes present were largelyremoved by reducing the pressure on the system and simultaneously raising the temperature to. C. V I

Upon increasing the temperature slowly to 60 C., a. small quantity of an intermediate fr'ac tion containing 50% butadiene was obtained.

Further heating at a temperature above C.

resulted in the isolation present in the original 9. 98% product.

I find that in of 80% of the butadiene fraction in the form of the practice of my invention as the number of cycles of operation increases some polymer accumulates. This polymer is of a character different from that formed when my invention is not employed in that it does not interfere markedly with the emciency of the solid as. t.

in the form of a product con- Furthermore, as the quantity of polymer increases its rate of formation decreases. For example, during the first fewcycles of operation polymer may be formed-at the rate of approximately per cycle basedon solid salt. This rate decreases as the number of cycles increases 1 so that when the number of cycles reaches say 100, therate of formation of polymer is found to have'dropped to A0 to /100% per cycle. In each of the foregoing examples, the elimination of the organic basic substance from the absorbent resulted in a substantial deposition of insoluble polymer in the cuprous chloride ab- 'siderable solubility sorbent. The rate .of deposition was so rapid in each case as to render the further use of the absorbent impracticable after only a very few cycles of operation.

As indicated previously, one or more organic basic substances may be employed for my purpose. If desired, such substance or substances may be added directly to the material to be, or undergoing, treatment in view of its or their contreatment of the reagent salt or salts with such substance orsubstances is particularly advantageous and is preferred. v

A number of solid, dry salts of groups 1 and 2- of the periodic system may be employed together for concentrating olefines, and particularly dioleiines, the monovalent salts being preferred. Excellent results may be obtained by the use of one or more monovalent salts of silver, copper, or mercury.

An outstanding feature of my process is that it is carried out in a substantially non-aqueous system, or in other words in the substantial absence of water. Since in industrial processes of this general character the presence of some moise ture is unavoidable, such moisture should not be permitted to accumulate in quantities greater than 2% by weight of solid dry salt and preferv ably not greater than 1% by weight of said salt.

Substantially lower tolerances are recommended.

While various procedures "have been particconsiderable variation. Therefore. understood that the foregoing specific examples are given by way of illustration. and that changes, omissions, additions, substitutions, and/or modifications might be made within the scope of the claims without departing from the spirit of the invention.

I claim:

1. A process for concentrating a light oil diolefine fraction containing olefine material .comprising contacting the same with powdered cuprous chloride containing not more than 5% by weight of an organic amine and in the absence of more than 1% by weight of'water based on said cuprous chloride, said contact taking place under conditions of temperature and pressure such as to form a diolefine-cuprous chloride association product, and thereafter heating in a stepwise manner to produce tion and a concentrated diolefine fraction.

2. A process for concentrating a light oil butadie'ne fraction containing butylene comprising contacting the same with powdered cuprous chlo.

ride containing not morethan 5% ofan organic amine and in the absence of more than'l.% by weight of water basedon said cuprous chloride,

said contact taking place underconditions of -therein. However, prior a concentrated oleflne fracduce a concentrated butylene fraction and a concentrated-butadiene traction.

3. A process for concentrating-a light oil isoprene fraction containing 'amylene comprising contacting the same with powdered cuprous chloride containing not more than 5% of an organic amine and in theabsence of more than 1% by weight of water based on said cuprous chloride, said contact taking place under conditions of temperature and pressure such as to form an isoprene-cuprous chloride association product, and thereafter heating in a stepwise manner to produce a concentrated amylene fraction and a concentratedisoprene fraction.

4. A process for concentrating a light oil piperylene fraction containing amylene comprising contacting the same with powdered cuprous chloride containing not more than 5% of an organic amine and in the absence of more than 1% by weight of water based on said cuprous chloride, said contact taking place under conditions of temperature and pressure such as to form a piperylene-cuprous chloride association product, and

thereafter heating in a stepwise manner to produce a concentrated amylene fraction and a concentrated piperylene fraction.

5. A process for concentrating a light oil butadiene fraction containing butylene comprising contacting said fraction with powdered cuprous chloride admixed with a hydroxy alkyl amine in proportion of not more than 5% by weight of said cuprous chloride, said contact taking place in the absence of more than 1% by weight of water based on said cuprous chloride and under conditions of temperature and pressure such as to form a butadiene-cuprous chloride association product, and

said association product by the application of heat to produce a concentrated diolefine fraction.

8. A process for concentrating a light oil diolefinefraction containing olefinic material which comprises contacting said fraction with powdered cuprous chloride admixed with triamyl amine in j proportion of not more. than 5% by weight of said cuprous chloride, said. contact taking place in the absence of more than 1% by weight of water based on said cuprous chloride and under condi= tions of temperature and pressure such as to form an association product between diolefine material contained in said traction and said cuprouschloride, removing olefinic material from said association product, and thereafter decomposing said association product by the application of heat to produce a concentrated diolefine fraction.

9. A process for concentrating a light oil diole= fine fraction containingl-olefinic material which comprises contacting said fraction with powdered cuprous chloride admixed with triethanolamine in proportion of not more than 5% by weight of said cuprous chloride, said contact taking place in the absence or more than 1% by weight or water based on said cuprous chloride and under conditions of temperature and pressure such as to form an association product between diolefine matethereafter heating the reaction mass in a stepwise manner to produce a concentrated butylene fraction and a concentrated butadiene fraction.

6. A process for concentrating an unsaturated hydrocarbon selected from the group consisting of olefines and diolefines which comprises contacting a fluid hydrocarbon mixture containing said unsaturated hydrocarbon to be separated and hydrocarbon material or lesser unsaturation than said unsaturated hydrocarbon to be separated with a solid powdered monovalent salt of a metal selected from the group consisting of copper, silver, and mercury, said contact being effected in the absence of more than 2% of water and in the presence of 0.1% to 10% by weight of said salt of an organic base and under conditions of temperature and pressure such as to form' an association product between said unsaturated hydrocarbon to beseparated and said salt, removing hydrocarbon material of lesser unsaturation from the reaction mass, and thereafter decomposing said association product. to obtain said unsaturated hydrocarbon in more concentrated form.

7. A process for concentrating a light oil diolefine fraction containing olefine material which comprises contacting said fraction with a reagent containing a solid powdered monovalent metal selected from the group consisting of copper, silver, and mercury, and containing not more than 5% by weight of an organic base, said contact taking place in the absence of more than 1% by weight of water based on said solid salt an under conditions 01' temperature and pressure such as to form an association product between diolefine material contained in said fraction and said salt, removing oleflne material from saidassociation product, and thereafter decomposing 7 rial contained in saidfraction and said cuprous chloride, removing olefinic material from said association product, and thereafter decomposing said association product by the application of heat to produce a concentrated diolefine fraction.

10. A process for separating diolefine material in more concentrated form from a fluid hydrocarbon mixture containing said diolefine material and oleflne material, which comprises contacting said mixture with a reagent comprising a finely divided intermixture of a solid powdered monovalent salt of copper with up to 5% by weight based on said salt of a liquid organic base, said contact taking place in a substantially non-aqueous system and under conditions of temperature and pressure such as to form an association product or said salt and said diolefine material, removing olefine material from said association product, and thereafter dmociating said association product in a manner to recover said diolefine material in more concentrated form.

11. A process for separating diolefine material by weight 50 in more concentrated form from a fluid hydrocarbon mixture containing said diolefine material and olefine material, which comprisescontacting said mixture with a reagent comprising a finely divided intermixture ot a solid powdered weight based on said salt or an organic amine, said; contact taking place in a substantially nonaqueous system and under conditions of temperasalt 0! a 'ture and pressure such as to form an association v 80 product of said salt and said diolefine material, removing olefine material from said association product, and thereafter dissociating said association product in a manner to recover said diolefine material in more concentrated form.

12. A process for separating diolefine material in more concentrated form from a fluid hydrocarbon mixture containing said diolefine material and olefine material, which comprises contacting said mixture with a reagent comprising a finely divided intermixture of'a solid powdered monovalent salt 01 copper with up to 5% by weight based on said salt or an alkyl amine, said contacttaking place in a substantially non-aqueous system and under conditions of temperature and pressure such as to form an association prodmonovalent salt 01' copper with up to 5% bynot of said salt and said dioleflne material, removing. oieflne material from said association product, and thereafterdissociating said association product in a manner to recover said diolefine material in" more concentrated form,

13. A process for separating dioleilne material in more concentrated form from a fluid hydrocarbon mixture' containing said dioieflne material and oleiine material, which comprises conflneiy divided intermixture or a solid powdered amine, said contact taking place in a substantially non-aqueous system and under conditions or temperature and pressure such as to form an association product of said salt and said dioleflne material, removing oleflne material from said association product, and thereafter dissociating saidvassociation product in a manner to recover tactinz said mixture with a reagent comprising a 10 said dloleflne material in more concentrated form.

FREDERICK W.

monovalent salt of copper with up to 5% by weight based on said salt or an hydroxy aikyl 

